text:
Why did my IAH-SYD flight avoid Mexican airspace?
I'm on UA101 tonight, the very long IAH-SYD nonstop operated by United.  If we look at Flightaware's routing for the flight (verified by the seatback moving map display) it's clear that we departed IAH, flew over El Paso and into southern California, left US airspace just west of Los Angeles, and then proceeded on the "normal" transpacific routing to Sydney.

Source: flightaware.com
What I can't figure out is why we specifically took this routing: it certainly appears that the point was to avoid overflying Mexican airspace, but I can't figure out why. United and lots of other US airlines provide service to Mexico so it's not like the airspace is off limits or anything.  According to gcmap.com the routing we took tonight adds about 300 miles (~40 minutes) to a route that is already VERY long, and the 787-9 that we're on has to be very nearly at MTOW anyway, so adding another 40 minutes of fuel is on the heaviest (i.e. most expensive) marginal part.
The economics of airline travel don't usually allow for things like this - burning a few thousand extra pounds of Jet-A doesn't make for good business.  Now obviously there's some reason for this routing, but I can't figure out what it might be.  I also looked at a few of the other routings for this same flight, and just a couple of days prior the flight did take a more direct routing over Mexico on the way out.
The winds aloft didn't look meaningfully different - Foreflight computed the times as we'd expect, the "longer" one was ~40 minutes more ETE.

Overflight fees might factor in

Looking at the current FlightAware history for UA101, it’s been avoiding Mexico since the departure on 26 Feb, but before that it’s been overflying Mexico routinely, so I don’t know what’s happened since the 26th. I doubt it’s weather-related, since Qantas 8 (which flies a relatively similar route from DFW–SYD) has been flying over Mexico recently.

Could it be an ETOPS thing? It has to be further north as it crosses the pacific?

It's too late now, but considering you posted this during your flight, but don't forget you can always ask a flight attendant the question, or ask them to ask the pilot.

@BruceWayne: the couple of times I’ve asked flight crews these questions the answer I’ve gotten (consistently but politely) is something along the lines of “We get the routing from operations or planning (or some other department) — we just punch it into the computer and fly it...”

Though routing this far north seems to make the flight about 200 miles longer, flight duration doesn't exactly correlate to route length. For a flight this long, wind plays a large role.
Take a look at the image below of the current wind forecast from ADDS, with the two flight paths in blue. You can see if they took the southern route over Mexico they would be flying directly into a pretty strong headwind. But by going further north, they can fly in much lighter wind conditions.

So I completely agree with your logic - and the map you provided makes it graphically clear.  But now I need to go and figure out why foreflight (which should have very current winds aloft data!) didn't compute any meaningfully different time enroute for the two routes I gave it (one direct, one IAH-ELP-LAX-SYD).  Hmmmm.


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How can I calculate the drag coefficient for a given wing design?
I am building an RC plane (for the first time. I am doing it for a competition) with a twin boom configuration like this:

My wing shape is like this:

I decided that the lift should be 0.8g and I need to use this equation to find the wing area (as per the instructions)
$$F_l=\frac{1}{2}\rho v^2 S C_d$$
$F_l=0.8$
$\rho=1.225$
$v=12m/s$
Can you help me in figuring out the value of $C_d$ considering that I am using Clark Y aerofoil design?
After that, I will measure $b$ using the aspect ratio.
$$\frac{b^2}{S}=\text{Aspect Ratio}$$
My instructor asked me to obtain a wing span of 80-100cm. So I will have to choose Aspect ratio as well.

Related: Airfoil Tools (select the Reynolds number) first.

You may visit http://airfoiltools.com/airfoil/details?airfoil=clarky-il
You can estimate the value of Cd from the plots. For different angles of attack, the Cd and Cl varies. So, you will have to select one based on your requirement.

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sort: votes


text:
Do fuel tank locations on the wing cause a potential for weight imbalance?
I have a question about fuel tanks in an older plane like a P-36C Hawk and a P-26B-35. The fuel tanks in the P-26 are placed in the wings and in the P-36C Hawk its under the pilot and behind him. For the P-26 or any plane with its fuel tanks on the wings would it cause more weight on one side if the fuel is used more then the other?

This is quite common in GA planes (the vast majority of Pipers and Mooneys) that have manual tank selection of the wing tanks. While the POH has recommended switching times you can still create an imbalance fairly easily.

YES
If the port and starboard tanks drain at different rates in a gravity fed system (due to a blocked valve or a clog in a fuel line), then eventually a differential in remaining fuel will drive a lateral imbalance in the plane's weight.  Another (and better) way of saying this is that the center of gravity will no longer be aligned with the aircraft centerline.
I can't comment on how this situation might emerge in the P-26 specifically, as I could not find a detailed enough description of its fuel system.
It is worth noting that the same is true with fore/aft center of gravity drift in aircraft where the tanks are located entirely in the fuselage (or under it).  This often has a more dangerous effect if not properly managed (and as a result the Cg drifts too far aft).
It is also worth noting that lateral asymmetry can also be created by non-simultaneous release of stores (like the 200 lb of bombs that the P-26 carried).  However, in the case of the Peashooter, the bombs were carried very close to the centerline, so the asymmetry would be minimal (as compared to that on a P-51 for instance).

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text:
Do Red Bull Air Race aircraft make use of nitrous oxide injection?
Microsoft Flight Simulator X contains Red Bull Air Race missions where the player flies an Extra 300S through a race course and makes use of Nitrous Oxide injection for the engine.  While I have heard of NO injection for automobile engines, I have never encountered an aviation engine which made use of this.  Can anybody verify if RBAR teams make use of this?

Isn't that just for making smoke, not improving horsepower?

This is from the 2014 season
http://airrace.redbull.com/en_US/article/lycoming-engines-power-behind-air-race

In previous years, the race teams were allowed to modify their
  aircraft, but since 2014, the engines and propellers have been
  standardised for all teams. The Lycoming Thunderbolt AEIO-540-EXP
  engine and the Hartzell 3-bladed 7690 structural composite propeller
  have both undergone rigorous testing and have performed to
  specification.

Here's a link to a smaller engine using nitrous to get 300 HP out of a 100 HP engine for record setting purposes
https://books.google.com/books?id=DhLSUHx136QC&pg=PA36&lpg=PA36&dq=lycoming+io-540+nitrous&source=bl&ots=UwecpWRA8S&sig=RgiMHhHnQuHJYph0TASw0Y6bB2o&hl=en&sa=X&ved=0ahUKEwieiZTGqf7aAhVxUd8KHc5uBLoQ6AEIhAEwDA#v=onepage&q=lycoming%20io-540%20nitrous&f=false
and even more HP here
https://en.wikipedia.org/wiki/Bohannon_B-1

I don't know that I'd want to be doing that to an engine that costs tens of thousands of dollars and has to last for several races over the course of a week/weekend, however long an event is.  Example:  http://www.airpowerinc.com/productcart/pc/TLEngineDetail.asp?catID=33&prodID=9462

Could be more like this, I don't see the AEIO-540-EXP listed http://www.airpowerinc.com/productcart/pc/TLEngineDetail.asp?catID=33&prodID=9741 No turbo on this one.

I'm not sure I see the answer in this post? Do they or do they not use NOx injection in the engines? They may be standardized engines but they could also be standardized NOx (I didn't read the links but answers should stand on their own).

No they do not. Inferred from the Airpower site and the Red Bull site, neither of which mentions NO as an option to order for IO-540 engine.  Read the links, I am not copying and pasting pages of copyrighted material that has been posted since 2014.

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text:
How can I calculate the speed gain from using multiple STC modifications together?
Looking at a parts manufacturer website, they list various STC'd modifications for Mooneys with estimated (cruise?) speed gains for each.
However, I've heard that those gains are not additive. For instance, if you applied three mods with 5mph gain each, the total gain would be less than 15mph.
Is there a way to calculate what the gain should actually be if you applied several at once, assuming the gains listed are accurate when applied in isolation?
Most appear to be aerodynamic improvements (i.e. reducing drag) but a few are engine improvements (i.e. increasing thrust). I'd prefer an answer that addresses both sides in an integrated way, if possible.

Can you explain further what you mean by speed gain? Is this cruise speed? Or Vmo? Hopefully not takeoff and landing speeds...

It seems pretty obvious that by reducing drag and increasing thrust that you would improve cruise speed.

@Jimmy Not specified, but I assume either cruise or maximum. I'd think the relationship would be the same.

@michaelhall Increasing thrust can also increase takeoff speeds, especially if it's a multi engine airplane.

Can you list the original source where you found this? Knowing what the mods are can help. Since cruise drag and speed are square related, they should not be additive.

I don't understand how increasing thrust would increase takeoff speed.

@Michaelhall For any aircraft, takeoff speeds are a balance of RTO and continued takeoff. For multiengine, you'd need to worry about Vmc/Vmcg. Increasing thrust negatively affects them.

Ok, I will concede that higher asymetric thrust in a multi engine failure scenario presents an issue, but my point is that it is quite clear from the context of the original question what the OP is after...

@Jimmy Added. I was hoping to get a generic answer, but I see now it may be easier to develop one from a specific scenario.

@StephenS Do you own a Mooney?  What model?  You would think that LASAR would have the data that gives the estimated aggregate improvements for various combinations of mods that they would be willing to provide for a potential customer no?

If you are modifying an A through G Mooney, do the cowl first then windshield.  There is at least 10kt right there.

@JohnK I'm considering buying a M20K and trying to figure out if I'll get more zoom for my buck by upgrading a 231 or just getting a 252.

Not practically speaking no.  With sufficient engineering data you could perform calculations to come up with a model for what the additive effects would be of the various modifications.
The problem with the aerodynamics to horsepower relationship is that almost all of the basic calculations have exponents.  So a mod that gives you 5 knots over a given 'stock' airspeed will not give you close to the same number at a different higher base airspeed.  So with three 5kt estimated improvements you end up with maybe 5 knots for first mod, 3kt for 2nd, and perhaps 1tk for the 3rd.  Add to that the complexity of really subtle interactions in aerodynamics could mean that one mod may make the other 2 yield no differences in cruise.
Take for example a TBM850 which cruises 300mph on maybe 800hp vs a Cessna 210 at under 200 mph on 300hp vs a piper cub going 100mph on 75hp.
Not apples to apples, but to give a sense of the scale these effects have.

I'm just making this up as I go along, so your mileage may vary.  Also I'm only dealing with the drag-reducing mods.  It seems this method ought to give a conservative estimate of the combined speed gains.
For each mod, seperately, calculate a "drag coefficient reduction factor" equal to stock airspeed squared divided by promised airspeed squared.  The number will be less than one.
When you' ve done this for all the mods you want to do, multiply all these values together.  Then invert that number, take the square root, and multiply by the stock airspeed to get your expected airspeed.
You may be able to treat power-increasing mods the same way, just treating them as an apparent drag reduction.

Yes, thanks, fixed.

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text:
Landing in very high winds
A few weeks ago, a storm passed through my area with winds reported at 55kt and gusting to 68kt.  Many light planes managed to break their tie-down ropes and were flung around the ramp area, which isn't surprising given the storm's winds were definitely above a typical light plane's VS0, VS1 and VR, possibly above VREF, VX and even VY.  Pilots being pilots, though, there were soon jokes about being able to take off and land vertically.
I understand that actually trying this would be a very bad idea, even before one considers the other aspects of the storm, e.g. lightning, rain, hail, low visibility, etc. that would make flying unsafe anyway.  I would never even think of trying it.  Still, it seems like an interesting theoretical question.
Is it even theoretically possible to "land" or "take off" in such winds, at least within the usual meaning of those words?  I can see that you could fly to touchdown easily enough, but how would you stop flying?  How could you taxi and secure an aircraft when you need significant power just to not go flying up (and probably backward) off the ramp?

Related: Is it an acceptable practice to take off in a microburst?

In an unmodified GA aircraft gusty winds would be beyond any reasonable safety limits.
In a steady wind the trick would be to reduce your AOA to a point where your airspeed no longer generated enough lift to exceed the weight of the plane.  Immediately raising flaps after touch down and heavy braking would increase your chances (you may not have much
ground speed at all anyways!).
The Space Shuttle Orbiter used a shortened nose wheel strut to help hold the
runway after landing at over 200 mph (making its own Category 5 hurricane).
Once the nose dropped through 0 lift AOA and into negative lift AOA, the wind would
actually help hold it on the runway.
But for the average Cessna, the best move is not to put yourself in that situation.
Check weather before flying, and divert to a safer airport if you can.  A large airport with
long, wide runways and someone to help you would greatly improve the odds.
If you had to land, it would be directly into the wind. Once down, taxi into the wind with
some down elevator.  I would be screaming on the radio for people to help secure the plane.
But if you get down, save your life first, then the plane if you can.

+1 for last sentence

indeed. I've seen the aftermath of a very heavy storm on improperly secured commuter planes, and it wasn't pretty. That same storm would have blown an unsecured C172 right into the side of a hangar (or another aircraft). Bad enough if nobody's on board, but if you are on board it's far worse.

It can be done. Some bushplane action...

Video link is broken.


text:
Why do RNAV airways exist?
I assume there's some stupidly obvious reason that I'm missing, but why bother creating RNAV airways when I thought the entire point of RNAV was not needing to fly along a suboptimal preset path?
I can see the need for waypoints, especially around the corners of restricted airspace that you'd need to dodge rather than just flying direct everywhere, but I'd think an RNAV flight plan would just be a handful of such critical waypoints--no "airways" needed.

RNAV freed aircraft from the airways that were already in place that may have zig zagged from VOR to VOR, but with the limitations of the ATC system based on human controllers, it is still desirable to keep most aircraft on a "road network" so to speak to make it easy to manage separation, so RNAV airways were created between major centers that provide straighter roads between cities you might say.
Try to imagine thousands of flights going hither and yon all on their own random tracks, instead of being fed along specific airways, without a bank of supercomputers to manage the separation, and you can see the problem that the RNAV airways solved.

So basically ATC still needs us flying preset paths so they only have to manage high-angle conflicts at intersections rather than low-angle conflicts everywhere, and RNAV just means those paths are more numerous (and hopefully more optimal) than before?

Thanks @757toga  I tried out for ATC in Canada once in the 80s and took the initial screening exam in a room with about 50 candidates.  50 multi-guess questions relating to 25 radar screen diagrams where you had to look at tracks and a table of their routes/altitudes and determine if there would be conflicts.  I didn't track the time and the exam ended when I was at question 46.  I got 2 of 46 wrong, thought 88%, great, the pass was 80%, but found out later you had to get 90% to be selected. If I'd just randomly answered the last 4 questions in the final seconds I'd probably have made it.

Note that nowadays with improvements of computers assisting the controllers, completely free routing is being used more and more. Austria has already deleted airways from all its airspace except the narrow Tirol “tail” and whenever I try to compare flight routes (from FR24) over Czechia or Germany with airways on SkyVector map, there is usually no correlation at all.

What amazes me is how RNAV was originally developed in the late 60s during the Integrated Circuit era prior to the microprocessor, coming up with a way to virtually relocate VORs using analog solid state electronics and not with software.

There's still another reason to use the RNAV airways, in the low altitude environment. Airways have built-in transitions to approach procedures, whereas direct routes do not. This saves work for both the controller (who doesn't have to issue an altitude restriction for an approach from an airway), and the pilot, who has access to more transitions for an approach.

RNAV airways are there for several reasons: (Speaking as a US controller and instructor)

Radar performance. Radar is not everywhere, and neither is ADS-B. Regulations require GNSS aircraft to be established on valid point-to-point routes, either using charted fixes within certain distance criteria, or flight checked airways unless in radar contact. This aids in search and rescue.
Flow control initiatives. Imagine, if you will, 100 air carrier aircraft all trying to get to KORD (Chicago O'Hare) at exactly the same time. Can't be done. Routes are established that Chicago ARTCC requires these aircraft to be on, and with miles-in-trail initiatives to keep the aircraft in an orderly flow.
Weather. Weather is constantly on the move, and issuing airway routing is often easier than issuing point-to-point, and, it's easier to understand. It's also faster, and less prone to error.
Transitional flight. Airways have built-in transitions to standard terminal arrival routes (STARS) and to approaches. Verbiage is shortened (again) when using them, because a controller does not have to issue an altitude restriction to a pilot when clearing an aircraft on a Standard Terminal Arrival Route, because the altitudes, speeds, and other instructions are printed on the STAR. Similarly, altitude restrictions can be omitted on an airway transition to an approach, whereas, on a direct route, a restriction must be issued.

Whenever a procedure (in this case, an airway) can be used to reduce confusion, conflictions, and verbiage, it's a good thing.

You are partially correct, first of all they are called "RNAV routes" not "RNAV airways" and yes the entire point of RNAV was not needing to fly along a suboptimal preset path but that was because of the fact that you flight plan had you flying directly over the navigational beacons. Like this:

RNAV routes allow more efficient flight by connecting random positions by selecting routes more freely, in addition to shortening the flight distance than conventional airways. RNAV routes  also provide you with following features:
1) Expansion of airspace capacity : Reduces lateral separation, allowing to double or quadruple the tracking of flight paths.
2) Reduce flight time and distance
3) Reducing flight cancellation and delay

This doesn't answer the question.


text:
Are intersection takeoffs less common in the USA than in other countries?
On a recent trip through Australia I did a number of intra-oz flights.  In at least three of the cases we performed intersection takeoffs, a couple at MEL/YMML and one at BNE/YBBN.  I have at least a thousand domestic flights within the USA, and although I wouldn't bet my life on it, I can't remember ever doing an intersection takeoff there.
The MEL/BNE runways are quite long - even with the intersection takeoff the available runway was over 8,000 feet in each case.
Am I wrong that this is super rare in the USA?  Are there airports where intersection takeoffs are commonly used, and maybe I just never fly through those?  The advantages are obvious, it saves taxi time and fuel, and a 737-800 on a 75 minute stage can't be anywhere near gross weight anyway.  In the USA, airports like HOU/MDW have runways that are shorter than our takeoff roll, which strongly suggests there's no outright safety issue... and these airports handle hundreds of 737-800s a day identical to the QF/VA ones I was on here.  What other things am I missing here?  Are the aussies just more time/fuel conscious than us yanks?  ;-)

And as SOON as I write this up, we did an intersection takeoff at ORD yesterday...

Although this question seems to be regarding airliners, some CFIs and flight schools discourage intersection departures out of safety concerns. The mentality is that having useable runway under you for as long as possible is the safest takeoff method. At least until you get to a safe altitude for a power-out landing.

US airlines are extremely fuel conscious. They have software that calculates the exact throttle and flap settings required for the exact length of runway available so that they don't burn any more fuel than necessary, and that is all typically computed before they even push back from the gate.
If the pilots know in advance (e g. from the ATIS) that intersection departures are in use, they'll calculate for that. However, if they're already taxiing out to the end and ATC asks if they can accept an intersection departure instead, they'll need time to rerun "the numbers" and reconfigure the aircraft. US ATC has learned from experience that this delay often negates whatever trick they were trying to pull off, so they usually don't bother asking unless there's a really good reason.
Also, unlike light planes, for safety reasons airliners are required to have enough runway available to accelerate to V1 (nearly rotation speed) and then brake to a stop again before the end if they need to abort. This means they'll rarely use more than about half the runway available. This is factored into "the numbers", of course, and is another reason why they need to be checked before accepting an intersection.
As to why intersections seem more common in Australia, perhaps there is some difference in how their airports are designed, or perhaps their ATC is just more willing to do it, or perhaps Qantas pilots are faster at running "the numbers" or have a habit of running all likely options instead of just the expected one.

While I agree with all the points you make, I don't think there are any differences between the US and the rest of the world in what you describe. OP is asking specifically about differences between the US and the rest of the world

@Bianfable Yes, V1 rather than Vr. Fixed that. But IIRC light twins don't have the balanced field requirements; it's Part 23 vs Part 25.

@StephenS Thanks for the update. You're right, light twins actually don't, but AFAIK it's not just airliners.

So this is somewhat helpful, but when you’re looking at a 10 or 11 thousand foot runway on a short 737, the runway length is not an issue- you only need half of it (see comparison to MDW/HOU).  Perhaps it’s just “easier” although more expensive to just run everyone out to the end regardless of whether they could use a shorter run or not.

@ljwobker A longer runway means using less thrust; they still have to run the numbers for whatever length they have, and if ATC changes the length, they're still required to rerun them even if it's "obvious" they have enough.

I always thought derated take-offs are to reduce engine wear. Turbines (and all heat engines) are most efficient at high power setting and the rolling resistance in ground roll is usually more than drag in flight, so I don't think derated take-off saves any fuel. It does save something on maintenance as the engine components last longer.

I fly them with a fair bit of regularity, then again I fly a PA-28 out of various Class D and C airports so my takeoff requirements are usually well under the available runway. Sometimes if you are in line behind a jet waiting for their IFR release the tower may give you a VFR departure in front of them from an intersection.
They say pilots are foolish for leaving fuel on the ground and leaving useable runway behind them.
The FAA has a fair bit of regulations to allow an intersection departure particularly at night:

f. An aircraft may be authorized to line up and wait at an intersection
  between sunset and sunrise under the following conditions:

The
  procedure must be approved by the appropriate Service Area Director of
  Air Traffic Operations.
The procedure must be contained in a facility
  directive.
The runway must be used as a departure-only runway.
Only
  one aircraft at a time is permitted to line up and wait on the same
  runway.
Document on FAA Form 7230-4, Daily Record of Facility
  Operation, the following: “LUAW at INT of RWY (number) and TWY (name)
  IN EFFECT” when using runway as a departure-only runway. “LUAW at INT
  of RWY (number) and TWY (name) SUSPENDED” when runway is not used as a
  departure-only runway.

g. Do not authorize an aircraft to line up and
  wait at anytime when the intersection is not visible from the tower.

Airline operational requirements may also require a full length departure.
All these things considered it can be simpler to just grant everyone a full length departure.

The departure-only part is relevant here... in AU we were most certainly using those runways for both departure and arrivals - both MEL and BNE are (functionally) single runway airports.

@ljwobker, not true: in AU (and specifically YMML and YMEN), it is very common to use one (of the intersecting runways) for departure, and another for arrival concurrently. It is also common to just use both; some of the aircraft (e.g. A380) may only be permitted on one of them.


text:
How far can a Super Hornet fly at max supersonic speed in a clean configuration?
How far can a Super Hornet fly at its top (supersonic) speed, assuming it's in a clean configuration, i.e. no external tanks and no ordnance?

Wikipedia says the Super Hornet's ferry range is 1,800 nmi (2,070 mi, 3,330 km)

Aircraft being ferryed typically cruise much slower than at max cruise, and can therefore exceed the "max cruise" range by a good amount.  Dan, any idea by how much?  HNY!  -Skip

An estimate:
An F-18E Rhino can only obtain its maximum speed of Mach 1.8 only at 36,000 ft in ideal air conditions and only in a clean configuration i.e. no external stores.
At 36000 ft at STP, Mach 1.8 translates to approximately 550 m/s or   1069 KTAS using the equations:
v = M*SQRT(g * R * T)
Where v is the velocity of the jet in m/s, M is the Mach number, g is the ratio of specific heats, R is the Ideal Gas Const. and T is temperature in Kelvin (use OAT at -40 C, 233 K).
Now an F-18E holds 14,400 lbs of fuel internally.  The GE F414 engine burns about 36,000 lbs/hr of fuel in full afterburner, so a total fuel burn of 72,000 lb/hr would be typical for this power output.  Assuming the Rhino could start at these altitudes and at Mach 1.8 with the tanks topped off, that gives us 14400/72000 = 0.2 hr or 12 minutes of flight time.  Ignoring upper level winds this would give us a maximum range of 213.8 NM.
This might be enough to put warheads on foreheads, then run like hell back to friendly airspace and a tanker or a carrier but it's not very good for a long range cruise profile.

The idea that you would run dry after twelve minutes really drives home just how fuel-hungry the full afterburner mode is.

I cannot provide a quantitative answer to the question, but can provide our tactical understanding of the situation in the light attack A7E.
The A7E was not designed to fight, but was designed to put bombs on target with long legs to and from. It could turn in a fight, but was not expected to win in the performance envelope, unless there was a coordinating flight of A7'S fighting. That said cunning and trickery have brought down a lot of aircraft in the air-air arena.
Our tactic was to come in low where our subsonic speed and relatively low fuel consumption put us at an advantage. Going supersonic has high fuel costs when you are at the ground, and little tactical adavantage. The idea was by the time they got behind your wingspan they had used a lot of their fuel. If they get behind your wing, jettison all stores and turn. If they are in burner, which they most likely will be because you have air-air missiles too,  all you have to do is last 30 seconds in the fight before they leave or burn out.
The F14 often went to burner in the cat. Their first call off the deck was, "Hey, where is the tanker!"

Perhaps in the "old days", but in their last 10 years, the F-14A could go to burner on the cat, not the F-14B or D. The B/D had too much chance of uncontrollable asymmetric thrust if an engine failed going down the cat-stroke, so they restricted to mil-power. Frankly, they had significantly more thrust out of each engine so it was rarely as much of an issue. (Tomcat bubbas typically had the same "tanker" jokes about Hornets, so I guess it's full-circle :-)

You know you are old when you not only scroll, but keep scrolling, to get to your birthday on a website. I remember talking to my grandfather, who has since passed away, about the Model T's he drove. And then there was the  day I was telling a WWI pilot I knew at the time about a tough simulator I went through. The instructor forced me to my standby attitude indicator and pressure instruments for a VOR approach, fluctuating oil pressure, and my divert field at minimums. He exclaimed, "Holy s&*t you had attitude indicators." Can't wait till that happens to me.

One of the things I truly enjoyed was circling the ship at 5000 feet with a buddy store. Alone in the cockpit, watching the deck on a beautiful moonlit night.


text:
Can I legally land an airplane in in Badwater Basin, CA?
Would it be legal to land a light plane in the Badwater Basin salt flats in Death Valley National Park?
Let me add that you can obviously land in the park, as you have runways at both Furnace Creek and Stovepipe Wells. So another way of asking is simply: do you have to have an official runway to land? Obviously, you would need to stay >= 500 feet from people, but people don't typically wander too far from the parking lot and that's a big area. Staying away from people wouldn't be too difficult, especially in July or August when there's basically no one in Death Valley.

Related

How far is Badwater Basin from Furnace Creek and Stovepipe Wells? I don't see it called out on a sectional at Skyvector.com.

Badwater Basin is about 14 miles south of Furnace Creek, although I think it stretches north/south for several miles. It's a big salt flat.

https://www.nps.gov/deva/learn/management/rules-and-regulations.htm says you would have to have special permission.

36 CFR §2.17 – AIRCRAFT and AIR DELIVERY

(a)(1) The use of aircraft on lands or waters within the park other than at locations designated by special regulations is prohibited.
  Death Valley’s special regulations at 36 CFR 7.26(e) authorizes the
  use of aircraft only at the following locations:

Death Valley Airport, latitude N 36°27’50”, longitude W 116°52’50”, commonly known as the Furnace Creek Airport.
Stovepipe Wells Airport, latitude N 36°36’15”, longitude W 117°09’30”.
The Saline Valley Warm Springs Airfield, latitude N 36° 48.41”, longitude W 117° 46.90”, commonly known as the Chicken Strip, is open
  pending special regulation.

The landing of aircraft at locations other than those listed above,
  such as for wildlife research, is permitted only under conditions of a
  permit issued by the superintendent.
Aircraft have a significant potential for impacting park resources and
  human safety. By requiring permits for these activities, the
  superintendent can manage these activities and mitigate negative
  impacts.

"Aircraft have a significant potential for impacting park resources and human safety." The superintendent doesn't want you to crash your plane into stuff.


text:
How do I tell ATC that I don't have a transponder?
If my plane doesn't have a transponder and ATC tells me to squawk some transponder code, how should I respond? Is it just as simple as "I don't have a transponder"?
This is for the United States and for a plane with no electrical system, and obviously at a towered field where I would be communicating with ATC using a portable radio. No flight plans will be involved and I will generally be flying out of a class B field but within a class B umbrella. Flights will be VFR/daytime only.
EDIT: Looks like I opened up quite a can o' worms, here. I didn't know it would be this complicated. Just found this, too, which adds some more info. Thanks for the lively debate and the good suggestions.
https://www.aopa.org/training-and-safety/pic-archive/equipment/transponder-requirements
Looks like it's getting more and more difficult to escape government control. I think I may have to get a transponder. Hmmm.

If you are within a "Class-B umbrella" you are inside a Mode-C veil, and you must be equipped with a transponder.

Related

From the AOPA:

Flying into a Mode C Veil Without a Transponder
For flying into a Mode C veil without an operable transponder, the
  pilot needs to telephone the appropriate radar facility for the Class
  B airspace and ask for permission to make the flight. Upon agreeing to
  conditions (including direction of flight and altitude), the pilot
  will be given a code number that he will mention to the controller
  upon initial radio contact. This is the same procedure that a pilot
  with an inoperative transponder/encoder would use to fly in or out of
  the Mode C-veil airports for avionics repair.
The situation may be slightly different if the pilot is landing at a
  satellite Class D (towered controlled) airport within the veil but
  outside of Class B airspace. The approval is still given by the
  controlling radar facility via telephone. The radar facility may still
  issue the code number but may only require the pilot to contact the
  tower in the Class D airspace.
NOTE: You should not expect approvals at the busiest of Class B
  airports during their peak times or under difficult weather
  conditions, but if this telephone procedure can expand the utilization
  of your aircraft occasionally, then by all means, phone to find if you
  can "fit into" the system.

None of the answers have actually addressed the question in the title, instead (justifiably) focusing on the problem of you planning to fly within the Mode-C veil around a Class B airport without a transponder.
So to answer the question, ignoring the issue of whether you personally need a transponder for your situation... use the phraseology NEGATIVE TRANSPONDER, like so:

Podunk Approach, Skychicken 321AB, VFR request, negative transponder. Three-zero miles east of Podunk VOR, heading three three zero.

Controllers can provide radar services to primary-only targets for as long as surveillance capability allows. Obviously the controllers cannot use secondary-radar (beacon) methods of positively identifying your target, so they have to use one of the three primary-radar methods prescribed in the 7110.65 5–3–2:

The target appears on the scope within 1 mile of the departure end of the runway, and the tower controller told the radar controller that the aircraft was rolling.
The pilot reports both their current position relative to a fix (VOR, intersection, airport, etc) displayed on the controller's scope, AND their heading or route of flight; and a single target is observed which corresponds to that report.
The pilot reports their position such that the controller is satisfied that the aircraft is within radar coverage and should be visible on the scope; the controller issues an identifying turn of 30º or more; and a single target is observed making the turns.

Handily, the methods are presented in order of how quick and easy they are for the controller to implement.

@birdus 14 CFR 91.225:

(d) After January 1, 2020, and unless otherwise authorized by ATC, no
  person may operate an aircraft in the following airspace unless the
  aircraft has equipment installed that meets the requirements in
  paragraph (b) of this section:
(1) Class B and Class C airspace areas;
(2) Except as provided for in paragraph (e) of this section, within 30
  nautical miles of an airport listed in appendix D, section 1 to this
  part from the surface upward to 10,000 feet MSL;
(3) Above the ceiling and within the lateral boundaries of a Class B
  or Class C airspace area designated for an airport upward to 10,000
  feet MSL;
(4) Except as provided in paragraph (e) of this section, Class E
  airspace within the 48 contiguous states and the District of Columbia
  at and above 10,000 feet MSL, excluding the airspace at and below
  2,500 feet above the surface; and
(5) Class E airspace at and above 3,000 feet MSL over the Gulf of
  Mexico from the coastline of the United States out to 12 nautical
  miles.
(e) The requirements of paragraph (b) of this section do not apply to
  any aircraft that was not originally certificated with an electrical
  system, or that has not subsequently been certified with such a system
  installed, including balloons and gliders. These aircraft may conduct
  operations without ADS-B Out in the airspace specified in paragraphs
  (d)(2) and (d)(4) of this section. Operations authorized by this
  section must be conducted—
(1) Outside any Class B or Class C airspace area; and
(2) Below the altitude of the ceiling of a Class B or Class C airspace
  area designated for an airport, or 10,000 feet MSL, whichever is
  lower.

Please use quote formatting to make it clear what is a quote and what are your own words. Also, I don't see how this answers the question about phraseology with ATC.

The answer was already provided to the initial question by Ron Beyer: "Unable, not equipped"

@CrossRoads Ron added a comment, not an answer. There's a big difference: see this meta question for more details. Because this is a Q&A site, not a discussion forum, we expect answers to answer the specific question asked. You might like to review the [tour] and [help] for more information about the StackExchange model (none of this is specific to aviation.SE).

Could you at least explain what "paragraph (b) of this section" is about? The part you quoted only explains where it applies but not what the actual requirement is. And it still doesn't answer the question about talking to ATC.

@CrossRoads can you please edit your answer to address at least fooot's comment?

First I assume this is for VFR flights and I assume this is for flight following.  In the US if you are flying in Class G airspace or Class E below 10,000 feet you are not required to have a transponder.  In this case you would tell ATC that you do not have a transponder but if that were the case I would doubt the controller would want to do flight following as they won't have your altitude information.  You are not required to contact ATC if flying VFR in Class G and Class E airspace.
One exception to the transponder rule is that if you are flying an aircraft that was certified without an electrical system.  These are usually very old vintage aircraft and they literally have no electrical system and no radio either.  If that is the case you will have to pre-coordinate with ATC and the control towers of the departure and arrival airport to let them know you have no transponder or radio.  The tower can use light gun signals to let you know you have clearance to land.
If you do pick up a transponder for your plane be sure to install an ADS-B out transponder as these transponders will be required beginning January 1, 2020.

Let me clarify. You're on the right track in your second paragraph. This is for a plane with no electrical, so no transponder. Second, I would be using a portable radio to talk with ATC, so no light guns necessary. This would just be for normal taxi and takeoff instructions. I know they typically give a transponder code. Anything I need to do when they give me the code other than tell them I don't have a transponder?

No except to just clarify that you are flying VFR.  VFR aircraft usually squawk 1200 anyway.  I know at Class D airports they don't give you a squawk code if flying VFR but they probably would give you a squawk code in Class B and C airports.  What class airspace is your airport in?

Well, I wanted to know the answer in general so I could deal with any airspace, but I would be basing this plane out of Tacoma Narrows which is within 30NM of SeaTac. Tacoma is class D. SeaTac, of course, is class B. Okay. So it sounds like for class D airports, I don't even need to worry about that. I didn't know that.

@birdus: Mode C transponder is often required within 30NM of the primary airport of Class B airspace, regardless of the altitude or the underlying airspace type. So even if the airport you're concerned with is in Class D airspace, you may need a transponder.

@birdus:  The best answer for you is just to pre-coordinate with ATC before takeoff and let them know you don't have a transponder.  Fred Larson is right that if you are withing the Class B airspace 30 NM veil you will need a transponder regardless.  Only way to fly in that case is through pre-coordination with ATC to get a "waiver".  ATC is pretty flexible on these things if you pre-coordinate.

What Fred said:  You'll be within the SeaTac Mode C veil, and underneath the Bravo shelf.  A Transponder is required.  You cannot legally base the plane you describe at TIW.

"will be required after 2020."  No, after 2019.  Starting Jan 1, 2020.  "On January 1, 2020, when operating in the airspace designated in 14 CFR § 91.225 (outlined below) you must be equipped with ADS-B Out avionics that meet the performance requirements of 14 CFR §91.227. Aircraft not complying with the requirements may be denied access to this airspace."

@DLH:  They may be flexible about pre-coordinating for an occasional flight, but if the plane is to be based at TIW, it will need a transponder.  They won't make perpetual, regular exceptions that close to SeaTac.

Can someone point me to documentation that says that planes that weren't built with an electrical system are going to need transponders/ADS-B?

@birdus:  The best thing for you to do is contact your FAA Standards Office and give them your situation and work it out with them.  You may want to look for an airport outside the 30 NM veil to make your life easier.

birdus, see answer below.

This doesn't answer the question about how to communicate with ATC

OP said he was "obviously at a towered field where I would be communicating with ATC using a portable radio."  And the "Unable" response was already addressed.

@birdus: Apparently it is possible to install a transponder in a vintage aircraft with no electrical system.

@Fred Larson, that was nearly 7 years ago, things may have changed with FSDO/FAA approvals now.  For example, I am trying to change the tailcone on my airplane to a more aerobatic shape, parts are made in Canada with Canadian STC approval. US FAA is requesting the OEM to go thru the full US STC approval process and won't sign off on the 337 my AP/IA submitted.  For 2 lousy pieces of fiberglass!


text:
What training is required for a class B endorsement?
14 CFR 61.95 requires solo student pilots to have an endorsement to (a) fly through class B airspace or (b) takeoff/land at a class B airport.  However, the requirements to get it are pretty vague:

(1) The student pilot has received both ground and flight training from an authorized instructor on that Class B airspace area, and the flight training was received in the specific Class B airspace area for which solo flight is authorized;

There are similarly vague training requirements for Recreational pilots in 14 CFR 61.101(d) and Sport pilots in 14 CFR 61.325.
Is any particular content or amount of time expected, or is it at the CFI's sole discretion to decide when a given pilot is competent enough to endorse? Does the training itself need to be logged as such, separate from the endorsement?

I can not find any guidance other than what you have already noted for Class B airspace endorsements. The ground and flight training requirements seems to be left up to the discretion of the CFI. Though, it seems to be very similar to a solo endorsement as having criteria that is subjective to student and instructor.
Similar to a solo endorsement, a conservative CFI would only endorse the student for a specific airport, in a specific Class B airspace (and not the actual Class B airport), for a specific timeframe, and specific conditions. Even though the endorsement must be given within the preceding 90 days of the flight, the conservative CFI would specify a specific date and time instead of a blanket authority.
That being said, your entire logbook would then serve as a record of adequate training. Previous corresponding flights with the CFI would be logged in the logbook as evidence of training.

As a side note, I live in an area with a very busy Class B. There are a lot of airports under the overlying Class B shelf. Each of those airports has a myriad of flight schools and independent CFIs. Those CFIs take their students into and through the Class B on a regular basis. Some even land at the Class B airport in the middle of the night when the tower is not as busy. So far, I have not personally heard of anyone giving or receiving a Class B endorsement for this area. As small of a sample size as my personal experience is.

Same with the B at my school, but my CFI had no problem giving it when I asked.  My night endorsement was another story!


text:
How do flight crews handle a death aboard a commercial aircraft?
Kinda a morbid subject I know, but whether a prince or a street sweeper, we all dance with the Grim Reaper - sooner or later.  And there’s no reason he cannot visit you at 30,000 feet, if it’s your time.  Therefore if a person, or a member of the flight crew succumbs and dies, how is this handled in a professional manner?

That's what ejection seats are for.

Burial at sea for transoceanic flights?


text:
What is the power generating capacity for an airport GPU?
What is the normal current for GPU power supply for commercial aircraft and how much power do they need while on ground (in kWh)?
I have read that aircraft need need 28V DC and 115V AC - what would be the percentage between both modes of supply?
Would it by possible to power GPUs entirely by solar power?

You mentioned commercial aircraft but tagged this with general aviation. Are there specific aircraft types you are interested in? The power requirements will depend on aircraft size and type.

kWh is a measure of energy, not power. Energy is power applied over time.

@andrewmh20 Nope, you're backwards. See here for example.

@andrewmh20 Wh is watts multiplied by time. Power has the time component divided out.

@andrewmh20 I'm a software engineer at a company that produces watt-hour standards - I'm pretty sure I'm correct. Anyway, this is off-topic and we've discussed it enough. Believe what you will.

@andrewmh20 One last comment - I think you're misinterpreting "applied over time". In this case, "over" does not mean division. It means multiplication. Power is integrated over time, and the area under the curve, if you were to plot it, is the energy. One dimension is power, one dimension is time. The area is power * time, also known as energy. And I never mentioned arguing..

Power requirements are dependent on airframe and configuration (see this question for a general idea). GPU's come in varying sizes for varying aircraft types. For example this GPU (arbitrarily chosen) can deliver: 800 amps continuous, 2500 amps peak. While this GPU can only drive 70Amps continuous. Others may be able to drive more and some may drive less. Are you asking about a particular application? The GPU's at the tiny airport I fly out of that we use to bump start the occasional Piper are no where near the capacity of what you may find at JFK for starting up a 747.

Would it by possible to power GPUs entirely by solar power?

Depends on the application but it would be unlikely to chose such a medium for powering a GPU the way things stand now (in terms of power requirements). You may be able to have a battery powered GPU that is charged by solar cells but that would only work well in the smaller scenario. Having a solar powered airport that can provide ground power is a whole different question.

An accepted energy density for the raw solar power on the Earth is 1.3 kW/m² at noon with no clouds. Cells are about 25% efficient for conversion into current (higher efficiency cells exist only in labs at the moment).


text:
How can I get started on a winglet design for a small remote controlled aircraft?
I'm a member of a student competition team, we design light aircraft (total airplane overhead area is limited to 0.9 m²) capable of carrying higher payload. The competition also limits the takeoff distance (this year's limit was 70 m).
Coming from the last event, we decided that winglets are probably a great introduction to the project, but we have no idea how to design one.
My question is basically: with this kind of aircraft (weighs about 2.3 kg empty, carries about 13 kg, wingspan is 2.8 m), what should we look for in a winglet design?
We are mostly in doubt about what kind of airfoil should we use. Should we look for less drag? More efficiency? How can we maximize the traction vector, and should we do that in first place?
We have been reading papers on the subject, but with little luck. We also don't think it would be wise to just randomly test things until we get right, so a little bit of direction would help a lot, even if it's an article that we should work around.
Thanks in advance!

Are you looking for a winglet design or airfoil design? Your title and question don't really match.

I'm unsure if the teminology is correct, in portuguese it's the same. But what I meant with airfoil is winglet airfoil selection.

What are the constraints? Winglets would make sense if you have limit on wingspan and not much otherwise.

@JanHudec The total airplane overhead area is limited to 0,9m^2, as of this year's rules.

The efficacy of winglets in large(r) aircraft is not recognized universally. Many engineers are of the opinion that they are nothing more than a salesman's gimmick. Just my opinion, but you might consider letting go the thought that winglets will be anything but a time-waster, from design to implementation, and just "build a better plane"

For best results, put good flaps on the wing and forget using a winglet.
If you insist on bending the wing up at its end, just continue with the tip airfoil and select the incidence such that your circulation distribution over the wing and winglet will become elliptical when you plot it in a straight line. The small size of your airplane implies that you will not need to unload the tips to reduce root bending moment.

Ah, I think I got that. I'm gonna bring this up with the other members, let's see what happens.
Also, flaps are on our minds. On the current project, we had bad results with them because the wing airfoil had a lot of camber and deploying flaps were adding very little to lift while increasing too much drag. An aerodynamicist suggested us to look into multi-element airfoils, if we are to use flaps.
Thanks for the tips!

@CaioGuimarães: If your airfoil has what is called "rear loading" (high camber at the rear), it is ideal for slotted Fowler-type flaps. The best flap is thin and highly cambered. You will need to rejuvenate the boundary layer, so simple camber flaps will not help. Also, make sure to combine them with slats, especially at the outer part which have no slotted flaps.

authors: Даниель Мунирович


text:
Why would a jet engine use cannular combustors if the annular design is superior?
Why are cannular type burners used in aircraft engines if annular type have more advantages over it?

Probably useful: https://en.wikipedia.org/wiki/Combustor#Types

I'm not aware of any modern jet engine design that uses cannular combustors. Can you give some examples?

@OSUZorba From the wiki page: An example of a gas turbine engine utilizing a cannular combustor is the General Electric J79 The Pratt & Whitney JT8D and the Rolls-Royce Tay turbofans use this type of combustor as well.

@TomMcW - The J79 is from 1955 and the JT8D from 1960 - I'd be hard pressed to call those "modern". The Tay launched in 1984, and that's borderline "modern" at best.

@FreeMan I had "depends on what you call modern" at the beginning of my comment but I see that when I cut and pasted it from my text editor I didn't get that part for some reason

@TomMcW Considering jet engines were first deployed in the early 1940s, they have had a life of ~70 years, so I would not consider 50 year-old engines modern.

@TomMcW well, in that case, I'll give you a pass, but don't let it happen again!  ;)

@OSUZorba I just happened to notice that the article listed engines with cannular combustors so I threw it out there. I knew the JT8D was old but that was the only one I was familiar with on that list.

@FreeMan I'm really bad at cutting and pasting. I always end up cutting my hand or pasting my fingers together

The question says nothing about "modern".

What is meant by "superior"? Ask superior in which ways, and you may have the answer.

Single combustor cans are simpler to develop. To get the ignition and combustion process right in an annular combustor is quite a challenge. When the first jet engines were developed, Junkers decided for separate cans while BMW wanted to design a theoretically superior annular combustor. In the end, the troubles with the combustor meant that Junkers got their engine fielded much earlier, even though BMW had started their jet engine development before Junkers.
With today's CFD tools the annular design is not quite such a challenge any more.

Modern jet engines do not use can or cannular combustors. GE made the switch to annular combustors by at least the J85, which had a first engine to test in the 1950s. The TF39 (1964) engine formed the basis of the CF6, which also uses an annular combustor. I don't know of any GE engine since the TF39 that did not use some form of annular combustors.
Modern Pratt and Rolls engines also use some form of annular combustors, but I am not sure when they made the switch.

This answer, while tangentially related to the topic, does not address the question.

The first operational jet engine contract was awarded to GE/Allison as the J35 and was later upgraded to the J47. When I was at tech school for the J47 we were told GE was given the contract because they had steam turbines of similar size and quite literally modified the steam turbines to have cans and use jet fuel! The conversion was a no brainer for the cannulur design. I worked on the J47 in North American F86 Sabra jets and they were notorious for flame outs and hot starts.
The use of cannular in early jets was due to several factors. Some factors are...
1) Metallurgy was not advanced and it was easier to inject a cool layer of air on the inside surface of the can by multitudes of small holes. Today's advanced nickel alloys are more robust and annular design can withstand much higher heat.
2) Because the can metallurgy was poor, they burned up quickly. Replacing cans is relatively easy compared to an annular ring. If a can flames out, the rest of the engine is pretty much unaware, annualar engines need everything working correctly to keep the heat, pressure and air flow safely controlled.
3) Infrared heat was a major problem in early designs, the cans effectively blocked the rest of the combustion chamber from the infrared flame.
4) Early can igniters had lots of problems so they just had a couple cans with them and then used a flame tube between cans.


text:
Why does this plane not pitch up after a dive?
I've tested my RC plane yesterday. It's a canard. After hand launching, the plane goes straight, then I change the elevator to go down and it's going down, but when I pitch up the canard doesn't work and the plane crashes.

The plane is at full throttle.
When diving the plane slightly rotates to right.
Controls tested before flight.

Edit:

Airfoil is a NACA 2412, but tips gets a little thick (all cutting, sanding is done by hand)
No incidences.
One servo for the canard and one servo for the ailerons.
No thrust angle.

The plane:

CG is just in front of the vertical stabilizer (the little cross in the image)

I'm voting to close this question as off-topic because i think it belongs to http://robotics.stackexchange.com/

I disagree, if I read it correctly it is an elevator efficiency question, but needs polishing.

What airfoils, incidences and control deflections were used? You leave us guessing at what happened; if you provide more details we could narrow the possible causes down. Right now I guess it was flow separation (stall) on the canard, but without more details I am just speculating.

Thanks guys. I've updated the question with requested information. I hope to be useful (I also have a short video from crashing time).

Also, where is the CG?

@TomMcW, The little plus in front of vertical stabilizer.

What are the control deflections for the canard? IE: How far does it move in max up and down throw? Also, just to confirm, the back is not elevons, only ailerons?

@Greg Taylor Sorry for late reply, using canard as elevator, max deflections is about 30 degree, and yes the back is only aileron.

Thank you for giving more information, but I still have to resort to speculation. Here are some things you might want to consider:

A rear-mounted prop stabilizes the aircraft. Full throttle limits your control power. You would had a better chance of recovery with engine idle.
No incidence means that the plane needs to compensate for the c.g. location with elevator deflection alone. If your plane is statically stable, it would need to be trimmed with some elevator-down deflection for straight flight. This limits the maximum possible canard lift and your nose-up control power. Better give the canard a few degrees of positive incidence.

However, from the picture it might well be that you use a full-flying canard. In that case, the incidence is set automatically by trimming, and a nose-up command means increasing the incidence further. Now the control commands do not change the camber of the canard wing which reduces both the amounts of maximum and minimum lift possible. Better use a canard with a stabilizer-elevator combination to increase control power.
You talk of cutting and sanding. Are the wings and canard made from styrofoam? Then @TipStall is right: The plane lacks stiffness. Commanding a descent (what you described as "going down") increased the dynamic pressure and thus the forces warping wings and canard.
For now, I think you suffered a canard wing stall, but I am not able to say why. Either it was aeroelasticity (twisting of wing and canard) or insufficient control power. In that case, use a stabilizer-elevator combination for the canard, throttle your engine and maybe consider a less stable aircraft by shifting the c.g. back a bit.

The stabilizing effect of the engine prop will depend on the thrust vector. if its above the center of gravity it has a nose down effect which would be destabilizing in the example given in the question. I agree that it sounds like canard stall. If the canard has a large available range of motion i.e more than about 15 degrees nose up the canard would definitely have stalled.

@DJ319: The thrust vector only adds a pitch moment. This can be used for pitch control by changing the throttle setting, but does not add stability. The prop by itself acts like an additional tail surface which stabilizes the plane.

@ Peter Interesting I have never heard of this effect before. I will look into it  thank you. Do you by any chance have a paper or book I should look at to speed things along?

@DJ319: Try "Calculation of aerodynamic forces on a propeller in pitch or yaw" by Crigler and Gilman. NACA-TN-2585, downloadable here. Stability requires the forces to change with pitch and yaw changes.

My vote is that the surfaces aren't rigid enough and get twisted so much that the control surfaces can't overcome the effect. How floppy (non-rigid) are the wings and the canard surfaces? The wing looks to be sagging under its own weight! My thought too is that you're tail heavy, tail heavy will pitch both ways and you can get stuck in either positive or negative stall (or tuck). Tail heaviness causes the plane to tend towards going or falling flat like a leaf; it's usually strongest (leeast recoverable) when under the influence of negative G's. It doesn't matter whether the craft is upright or inverted; it's still "negative G's" including the caused airflows. Still, my best guess is weak surface rigidity. Good luck with your cool project!!!

Every wing reinforced with two 6mm fiber carbon pipe that connected to another wing with a 20cm 4mm steel bar, but tips gets a little twisted with hand.

@SAMPro: The carbon pipe adds bending stiffness but not much torsional stiffness. Better to wrap the full wing in one layer of glass/epoxy.

I would suspect a combination of a very nose heavy CG, and not enough up elevator control throw, but it's impossible to determine based on the information given.

@Federico it's an acceptable answer given the information provided. If the question gets updated, I'm sure he'll update his answer.

From experience I'd say the CG is a little tail heavy. It's a canard but with very big canards which makes it closer to a tandem. So I'd expect the CG to be somewhere in between the trailing edge of the canard and the leading edge of the wings.

@slebetman "I'd expect the CG to be somewhere in between the trailing edge of the canard and the leading edge of the wings." Well, that doesn't narrow it down very much!

To add to Greg's answer (which points to the two most obvious suspects), I'd say that a typical stable canard should have a higher incidence on the canard than on the wing. You can offset it with a constant pitch up trim, but apparently you don't have enough of it (for the chosen CG position).


text:
What do I request when contacting tower of an airspace I'm transiting over?
I'm a student pilot who has just begun dual cross-country with my instructor. However, he has not been explicit when I've asked him about radio comm with tower/approach/radio during the flight. If I enter an airspace (say, Class D) and contact the tower, but I do not intend to land there, what would my initial call to the tower be? And what are the differences in requests for approach/departure and tower?

Can we assume you're asking for the US airspace?

That would be correct, U.S. airspace.

State your call sign, where you are and what you want

This question really needs some help.  Title implies you may be transiting over the ceiling of the airspace, while body of question implies you are transiting through the airspace.  Please clarify.  I won't even mind if the clarification invalidates myn answer, I'll just delete it in that case.  (In fact I think I'll go ahead and do that now, since it's been well established on ASE that it is best not to answer a unclear question, instead it is better to ask for clarification.)

@quietflyer When the question is voted +14 and received 5 answers with one accepted with thanks for answering what the OP was wondering about, I have to think enough people found it adequately clear that closing it years later doesn't really accomplish very much.

It's the standard initial contact: who you are talking to, who you are, where you are, what you want.  "Madison Approach, Cessna 123AB, 15 miles south at 3000 feet, request to transition your airspace to the north."  If it's class B, C, or a TRSA your call will be to Approach and they will give you a squawk code and the local altimeter.  For class D, there is no approach so call the tower with the same request.

Thanks so much! And flight following can only be requested with approach/departure when transitioning?

There's not much reason otherwise. The two main reasons you're contacting approach at all are to transition or to land, and if you're landing you can bet they'll be keeping an eye on you. For Class B airports, flight following is typically available from the airport ATC anywhere within their "mode C veil", even if you're outside or underneath their actual controlled airspace. Most other VFR flight following services are handled by the ARTCC for the area.

Flight following is something you can ask for when not otherwise required to be in communication with the ATC. If you're transiting through an airport's airspace, you need to be in contact. If you are in Class E, or over or below B or C airspace, you can call ATC and ask for Flight following.

Nitpick, in any case there will be some sort of approach control (and I think in the modern era it will always be a radar approach control), whether provided by a TRACON or ARTCC. But you are correct that while tower may own more or less B/C/TRSA airspace than the surface area itself, for class D the tower is the controlling agency for all of the class D airspace.

I would make a small, but important adjustment to the transmission above: 15 miles south of what. Always give a fixed point as a reference to your location. Don't assume the receiver assumes your point of reference correctly. There's a high probability you both assume wrong.

This will vary for every airspace so lets go over them in descending order.
Class B (Bravo): First off, keep in mind for your future solos that as a student pilot you are not allowed to fly solo in class B airspace unless your instructor has given you training and a logbook endorsement for that specific class B (see 14 CFR 61.95). But if your instructor is in the plane then technically they are accepting the clearance, not you. For Bravo airspace a clearance is explicitly required and a typical exchange will go something like this:

PIC: "Philadelphia Approach, N123XY, 5 miles southwest of KPHL, at 4000, heading to KPNE requesting transition through Bravo airspace."
ATC: "N123XY, Philadelphia Approach, Squawk 0425 and ident, Philadelphia altimeter 29.92"
PIC: "N123XY, 0425 29.92"
ATC: "N123XY, Radar contact 4 miles southwest of KPHL. Cleared through Bravo airspace via present heading."

En route you may get traffic advisories or other instructions while in the space so you need to stay on the frequency.
Class C (Charlie): For Charlie airspace you only need to establish 2-way radio communication. A response containing your call sign will allow you into the space. Lets look at an example

PIC: "Allentown approach, N123XY, 20 miles to the southeast of Queen City at 3000 in bound for landing at Queen City"
ATC: "N123XY, standby"

Anytime you hear your call sign, it is considered to be the establishment of 2-way radio communication, if you hear "aircraft calling Allentown, standby", you have not established 2-way communication and must remain out of the space since they did not respond with your call sign. Likewise you may be explicitly instructed that you must remain out of the space.
Class D (Delta): Delta airspace typically  extends up to 2500AGL, and you can often climb over it flying VFR. You do not need to hail the tower when doing so but many people do so out of courtesy. If you intend to enter Class D, follow the same procedure as Class C.
You can find the whole breakdown here
Flight Following: Where available and workload permitting you may be able to pick up flight following while in route. You can also coordinate a hand off from them to the airspace you are entering.

Ahh silly me, you are correct, has been edited.

One small correction: solo student pilots are allowed in class B if they have training and logbook endorsements for that specific airspace (see 14 CFR 61.95).

I didn't know that about the call sign being a clearance. Nice!

@BrianTopping I don't think it is technically a "clearance", but you also don't need one. You only need to be in "two-way radio communications" (defined using the rules Dave gave). See 91.129(c) for class D airspace and 91.130(c) for class C airspace.

The way I think of it is that clearance to enter C/D space is implicit given two way comms. The controller can expressly deny you entry into his Charlie or Delta space even with comms established, so clearance is still a thing in these airspaces, but you don't need express clearance to enter like for Bravo space.

First, you should contact the tower before you enter their airspace. Class B (around big international airports) requires explicit clearance to enter, while C/D airspaces around smaller commercial, military and GA airfields require two-way communication with the controller prior to entry (clearance is implied if not expressly denied; you'll hear "remain outside" or "remain clear" if you shouldn't enter).
To initiate communication for any purpose, you usually start by saying the name of the ATC station you are calling, including the type of controller you need to talk to. Let's assume you're flying into Franklin Regional Airport (no clue whether such an airport exists or where it is, just an example). Most Delta towers have a single team of controllers handling every aspect of traffic control, and "Franklin Tower" will suffice. Depending on the airport, they may prefer you use more phase-specific controller names like "ground" (for taxi instructions), "tower" (for takeoff/landing clearance), "departure" (for routing from the runway to the edge of their airspace) or "approach" (for any initial contact where you start outside and want to come in), even if the same small team of controllers in or near the control tower handle all of these things. Since you want to transit, "Franklin Approach" is normally also acceptable. To be friendly (they are human after all) and also to indicate this is an initial transmission with a callsign they don't know about yet, you can start with a salutation, but it's optional.
You then immediately follow this with your callsign (usually the make and tail number of your aircraft, for instance "Piper 342 Lima"), followed by your approximate range and compass radial from the facility, and then your flight mode (VFR, IFR, VFR-On-Top), and finally what you want (in this case to transit their airspace).
So, your initial transmission would go something like this:

Good afternoon Franklin Approach, Piper Three Four Two Lima, five miles northwest, VFR, request transit to the southwest.

The response you'll get depends on several things. Usually, you will hear something along these lines:

Piper Three Four Two Lima, squawk 2451 and read altimeter tape.

This is their acknowledgement that you wish to enter and pass through their space, and for you to do so, they need to be able to identify you on their radar using your transponder, and know what your indicated altitude is (your Mode C transponder will tell them the same, but not all aircraft have Mode C reporting and it can take a few seconds for their display to update). You comply by setting your transponder and replying:

Piper Three Four Two Lima squawking 2451, altitude two thousand five hundred.

The tower's next move will usually then be:

Piper Three Four Two Lima, radar contact, proceed on course.

They are telling you that they can now identify your plane on their screens, and that you are clear to continue flying along your present course at your current altitude. They can, since they control the airspace, instruct you to turn to a different heading, or to climb or descend to a different altitude, in order to accommodate the normal traffic pattern or to route you around another transiting aircraft. If you need to turn, climb or descend without being instructed by the tower, it's usually good to request a heading or altitude change so the tower can make sure you're still going to stay clear of other traffic they control, especially IFR flights.
The tower can respond in other ways to your initial transmission. A critical distinction is that the controller must respond using your callsign in order for two-way communication to be established. If they respond to your transmission in any other way, communications are not established, and therefore you cannot enter their airspace. A common reason they wouldn't acknowledge you by callsign is that your transmission got garbled by other radio traffic or noise interference:

Aircraft calling Franklin Tower, say again.

... or you don't have your mike plugged in:

Aircraft calling, carrier only no modulation.

... or they're too busy to deal with you:

Aircraft calling Franklin Tower, standby.

Also keep in mind that if they heard you loud and clear and respond to you by callsign, they can still keep you out:

Piper Three Four Two Lima, remain clear, expect further instruction.

Even though two-way comms are established, you cannot enter their airspace if they tell you to keep out. If you hear this, their airspace is likely too full to accomodate an additional plane, even transiting. In such a case, if you can get where you're going without crossing their airspace, it's probably a good idea:

Piper Three Four Two Lima copies, cancel request, we will fly around your Delta.

If you can and wish to terminate communications with the tower at this point (since you're going to stay outside their airspace there's not much reason to keep talking to them), you can indicate this by ending your transmission with your callsign instead of beginning with it:

Copy Franklin Tower, cancel request, we will fly around your Delta, good day Piper Three Four Two Lima.

The tower then knows you have likely switched off their frequency and will not respond to further transmissions. If they need to contact you again, they'll likely try on the surrounding MULTICOM or UNICOM frequency, or on GUARD, but as long as you stay outside their airspace there would be little reason for them to try.


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How does EGT work?
I am making a report and how does EGT of an aircraft, either turbo or piston engine, work? Can you please give me the procedures... Like where it starts and being transferred to where and stuff. Thank you!

Have a look at: http://aviation.stackexchange.com/questions/233/how-does-the-mixture-of-an-engine-affect-the-engines-operation in addition to any answers you might get here.

@instcpat Are you asking about piston engines or gas turbine ones? I'm not sure about EGT in piston engines.

@aeroalias I mean for both pls :)

This is now the second time you have edited this question and completely changed the question. I'm also not sure what the current version is asking.

From all the NASA reports I could find they mostly use Thermocouples. They also use RTDs which sometimes are called PT100. I am not sure if termistors are used.
There is research on optical measurement, but right now I would say that Thermocouples and RTDs are the common way to measure EGT.

http://ntrs.nasa.gov/archive/
http://www.grc.nasa.gov/WWW/sensors/


text:
Why don't DO guidelines have examples?
As per DO-178 C section 6.2 Overview of Software Verification Activity

b. When it is not possible to verify specific software requirements by exercising the software on a realistic test environment, other means should be provided and their justification for satisfying the software process objectives defined in the Software Verification Plan or Software Verification Results.

After reading this every/most of verification engineers would understand it as other verification methods like Analysis, Inspection etc...
As per the discussion and Arguments "The real intent of this objective is how do we verify the software when hardware is unavailable" like, using simulator to verify the software needs to be documented under SVP for this objective satisfaction.
The question is, DO (document Order) as evaluated from version A, B to C now and still have ambiguities and different understandings. Why don't FAA/JAA can come up with examples or layman language explanations for each objective?

I guess because it would bloat the document.

@ratchetfreak but intent of creating new version to solve the ambiguities and different understandings for different people.

The moment you start listing examples, some will take them as normative. This might not be the reason, but it is certainly a reason why adding examples to legislation (or legislation-equivalent documents) is usually a bad idea.

Standards are not aimed at laypeople, they are aimed at engineers, and must engender independent diversified thinking. Providing examples will incentivize single solution copy-pasta warriors, which is a dangerous proposition in software safety.

@DeerHunter when I mentioned layman it meant simple language. The current discussion was between qualified engineers only.

@MichaelKjörling has a great point: spend some time on StackOverflow and you'll quickly find out how many 'professional' software developers simply copy and paste code blindly from documentation or other sources without ever understanding it. For critical systems you don't want "layman language", you want precise and unambiguous specifications. In extreme cases the specification can even become a kind of pseudo-code itself but that's the price you have to pay.

The question sounds like a complaint (or a suggestion) for the ambiguity for non-experienced engineers/developers. I believe any thorough elaboration of the topic would result in the correct understanding. Not only DO, but also other guidebooks (even standards) most of the time leave the door open so that "if you can't do sth the proper way, (try to) do something that is good enough, and plan for it"). If they do not leave this door open, it would ask for out-of-this-planet tests (test everything on real hardware!).

"Why don't DO guidelines have examples?". Of course nobody can know the reasons, but it's usual business that consulting firms discuss in depth the standards with authors and then provide support to clients that must use these standards. I'm not saying it's the best approach, just that it's common to see this profitable intermediation.

'As per the discussion ...' Which discussion?

RTCA documents are not FAA documents, although the FAA is usually a member of the Special Committee that creates the documents. If an example is to be added, it is the decision of the SC, not of the FAA.
The reason that no examples are given is that the recommendation is clear by itself. A good V&V engineer will read this recommendation and use his skill, experience and creativity to find an other acceptable means to validate the software requirements that can not be validated in a realistic environment. This alternative means is then documented in the SVP.
Giving an example is not helpful at all, since the solution will depend completely on the software under test and the nature of the requirements.
If the hardware is not available, an emulator may be the solution.
In other cases artificial test inputs have to be generated, because failing a test in a realistic environment may prove to be catastrophic.

The FAA interprets a limitation to its authority (which is derived from FAR 25.1309 for transport aircraft, for example): It is not supposed to say anything is required to demonstrate compliance (for a module of software or a system of hardware) and be approved in the context of a certified aircraft. It can (and does) specify certain steps which constitute acceptable means of compliance.
The documents in the "chain of authority", not only DO-178C and DO-254, but also AC 20-152, are always careful to say that alternative means of compliance may be acceptable.
The practical matter, however, is that if DO-178C is even plausibly appropriate for a software module, and if hardware being developed is at all within the ballpark of DO-254, the DER is likely to insist that those standards be followed.  And the FAA is certainly comfortable with that stance.  So although these documents are not normative, they are as important as if they were normative.
If the standards did include examples of alternative means of compliance, one of two things would happen.  Either these examples would be taken in the same semi-normative light that the rest of the standard is taken, in which case approval (where appropriate) based on some other means of compliance would be that much less likely to be accepted, or the existence of the examples would overly encourage developers to fight for acceptance of their own means of compliance, in cases where DO-178C is perfectly applicable.  The latter would surely generate "more heat than light."


text:
What is this airplane used for?
Every satellite picture I've ever seen of carriers in port usually shows a lot of equipment on the flight deck, presumably involved with servicing and overhauling the ship between cruises.  This example is from NAS North Island in San Diego.

A closer inspection of the stern of the ship shows what appears to be a derelict F-18 airframe parked on the flight deck and stripped of its engines, LE and TE flaps.

Usually the airwing is launched back to naval air stations on shore prior to the ship reaching port, then fly out again to trap aboard when the ship goes out to sea again and this jet doesn't exactly look flight ready.  What exactly is this aircraft used for?  Is it some kind of training device for shipmates or aircraft handlers or for training on firefighting techniques?

Looks like an F-18 in folded-wing configuration.

I was deployed on the USS Abraham Lincoln in 2005. This is most likely an old airframe used for firefighting and damage control training. A closer/clearer picture would be nice, but it likely doesn't have engines and may be missing other parts.

It's so people know it's still an aircraft carrier when sans air arm.

While I'm not sure about the condition of the aircraft, there are uses for a non-flight worthy aircraft in a carrier deck. For example, the crash and salvage team can train salvaging the aircraft, or the sailors can train craning the aircraft abroad the deck.
For example, in the image below, U.S. Navy sailors use a crash and salvage crane to lift a non-functional McDonnell Douglas F/A-18 Hornet during flight deck drills aboard the aircraft carrier USS Ronald Reagan (CVN-76).

By U.S. Navy photo by Mass Communication Specialist 3rd Class Jonathan Nelson - This Image was released by the United States Navy with the ID 150415-N-WO404-124 (next).This tag does not indicate the copyright status of the attached work. A normal copyright tag is still required. See Commons:Licensing for more information.
It may also be used for firefighting and damage control training, as can be seen in the image below.

Sailors assigned to the crash and salvage crew on USS George H.W. Bush (CVN 77) spray foam on an F/A-18 Hornet training aircraft during a firefighting drill; image from warbirdsnews.com, credited to USN
The article notes:

Since active jets are precious assets, they use specially-prepared training airframes, like grounded F-18 Hornets ... these former frontline fighters are often antiquated models of current equipment or planes that have been damaged beyond the point of repair. These days the trainers are usually represented by earlier models of the F-18 whose variant has been retired, ... (they serve) as training aids for firefighting and crash retrieval and salvage operations, letting crews hone their skills using real world items, without risking damage to expensive operational flyers

Thanks.  That's what I had thought.  I wonder if the airframe is carried during cruise, usually stowed in the hangar deck, and placed on the lid in port to remove clutter below.

@Carlo looks like... The linked article mentions it..

Yeah it appears be be a derelict F-18 airframe used for crash and fire training drills.  I’d guess, for whatever reason, the jet became unairworthy, so they cannibalized it for spares and then used the stripped airframe for this training role.

That is an F-18 with its wings folded up. See this photo:

Actually, upon closer inspection, it appears that the leading edge and flaps have been removed:

Oh I’m aware of what kind of an airplane it is.  I just wanted to know the purpose of a non-flyable airframe on the ship was.


text:
Which organizations and individuals are invited for a review before the first flight of a new aircraft?
The first flight of a new aircraft is a major aviation milestone for the company and the industry.  What departments or organizations (within a parent organization), and what individuals, are invited to the pre-flight review of a First Flight of a new aircraft?

What kind of stake holders are invited?
How many Technical guys are invited?
Is there any regulation by FAA to include a particular parties?

It truly depends on what company it is and how many dudes they want at this great event. Its more of an opinion based question.

I'm voting to close this question as off-topic because there is no definitive answer. Who gets invited is completely up to the organization testing the plane.

The level of contribution is your potential contribution to the particular flight test.
There are several levels:

Who gets a place in the aircraft? This should be test pilot(s) and maybe an engineer or two if the aircraft has enough space to carry them.
Who gets a place in the control room? This is the flight test engineer and systems engineers (experts for the engine, the control system, the landing gear and so on), also engineers familiar with the aerodynamics and flight mechanics of the plane. Generally, the number of people in the room should be kept small.
Who gets a place at the ceremony and press conference afterwards? Now only the test pilot is invited, and maybe the flight test engineer and the development project leader, but otherwise you will find mostly board members and PR people at the press conference. The engineers will be busy clearing the buffet at this time, anyway.

The responsibility to select who will get into the control room rests primarily with the flight test engineer and the test pilot. However, the whole aircraft development will already be observed by the FAA. From the FAA and Industry Guide to Aircraft Certification about the implementation of the planned flight test:

During this Phase the Applicant and FAA work closely in managing, refining, and achieving their agreed PSCP to ensure that all agreed upon product specific certification requirements are met.

PSCP = Project Specific Certification Plan
Normally, FAA engineers are reviewing the planning, but do not get into the details such as who exactly will participate in the first flight. The company developing the aircraft prepares a plan and FAA will approve it without much hassle if the company has a record of conducting flight tests. If the company is a startup, however, closer scrutiny must be expected.


text:
Do pilots adjust the throttle setting during a Red Bull air race?
During a race do the pilots adjust their throttle settings to control speed, or do they leave the throttle wide open the entire time?

The only reference I could find is here (watch the video too):

Pilots keep throttle on full for racing.

It is a race. Only the fastest one wins.

"It is a race. Only the fastest one wins." That's a non-explanation. Car racing is also a race in which only the fastest one wins but there, you don't have your foot to the floor the whole time.

Being the fastest is not enough. There are rules limiting load factor (and thus turn radius) and entry speed. Pilots may need to slow down to avoid penalties.


text:
What modifications are necessary to the airframe and or instrument panel to add an autopilot to a light airplane (like a Cessna 172 or 182)?
If you were going to add an autopilot to a light airplane that never had one, what all needs to be done? I know they need to connect servos somewhere (where exactly), and add instrumentation to the panel, but how invasive is the installation?

What kind of auto pilot? Single axis? Two Axis? Is it coupled to the GPS?

@RonBeyer I'm sure a good answer can cover all. Otherwise you'd have to ask three separate questions for incredibly similar topics.

I'm particularly interested in a two-axis autopilot coupled to the GPS. From the only answer (so far) it looks like it is very specific to each airplane. I guess I was looking for some general "servos for the ailerons are typically mounted here..."

I participated in a project to do this to a light aircraft some time ago. The requirements will vary on the basis of the type of autopilot you select and the requirements of the STC that comes with it, and which allows it to be installed on your aircraft. There might (and likely will be) one or more of the following requirements: panel mods, electrical mods, servos need to be installed (type, placement and installation procedure as per the STC), there will also have to be ground and flight testing, and if you intend to interface the unit to navigation equipment, then it gets really interesting. It all depends what other avionics you already have in your aircraft. You may or may not have to upgrade your existing equipment to achieve that.
To get a complete answer to your question for a specific aircraft you need to go to a reputable avionics shop that has done the work before (read: has references) and pose the question to them.
You should also expect to have to pay for a detailed quote and time estimate -- it takes quite a bit of work to prepare that, and avionics shop owners have to pay bills and put food on the table, just like you. :)


text:
Why is the Mooney's signature tail profile different from most planes?
In another question, someone said everyone but Mooney has the vertical stabilizer on backward. (As a Cessna driver, this looks backwards to me). Is there an aerodynamic reason or some reason other than marketing?
(Note the slants of the leading and trailing edges.)

Marketing. One "theory" offered is that the vertical tail has less frontal surface area and thus less drag.

Good luck for a factual answer!

Because if it looked the same as all the others, it wouldn't be a "signature"

Do you mean you pilot the Cessna 210 Driver or you mean you pilot another Cessna? It's a bit unclear.

The best explanation I've heard is that at high angles of attack the rudder is nearly vertical providing the pilot better yaw authority.  I don't know whether this is true or not but it makes for a good story, doesn't it?
The story goes something like this:As the plane pitches up, the rudder, being slanted "forward," moves closer to a vertical position and provides better directional control at low speeds.  Conversely, at high angles of attack a swept tail (and rudder) moves further away from a vertical position and is, in theory, less effective.
Some go on to speculate that the leading edge of the vertical stab, being un-swept, protrudes further into undisturbed airflow at high AOA/low airspeeds which may slightly enhance the pilot's ability to control yaw at the edge of a stall.
I've never spun a Mooney (I did complete my CFI in an M20F/201) nor do I have a burning desire to do so.  I imagine that it's not a friendly spinner.  Catching the spin early would be critical in a slippery air frame like a Mooney.
A brief online search of Mooney tail lore yields everything from pure marketing to discussion of wetted area to better directional control during landing to spin recovery/prevention to "those swept tails provide no speed benefit and are simply designed to look good."
Here is one discussion (of many) on a Mooney forum regarding the tail design: http://mooneyspace.com/topic/9905-mooney-tail-aerodynamics-not-backwards/
I doubt very much that it's simply a marketing gimmick (although, it could be as simple as that!).
I believe that the explanation I've relayed here is merely "somewhat plausible" as it was gleaned from hours of beer-fueled hangar talk and some Google searching...not exactly a scientifically rigorous method of research.  I have no credible references and, as far as I know, no data exists to back any of it up.

and I doubt that it is anything else than a marketing gimmick. So we agree to disagree, aren't we?

Sure.  Why not?  We can do anything on the internet!

Yet I could swear I've read on this site a suggested that a tail swept in the normal direction is more resistant to stalling at high angles-of-atrack!

You could be right.  And Peter has forgotten more about aircraft design than I will ever know.  My answer should be treated like a long comment.  I have absolutely nothing to back it up....just rumor and some speculation on internet forums.

I worked at Mooney for 11years, 6 as the Director of Engineering after Roy Lopresti left the company.  Art Mooney asked Al to design the wood spars so he could build them on a flat table. This resulted in t iconic and characteristic "Mark" of the M20 Type.

The tail only looks backward when people can usually see it: in the pattern, parked, or flying formation with a photographer in a slower aircraft. Rather than using trim tabs to push control surfaces out of alignment (which adds drag), the entire empennage pivots for pitch trim adjustments. To trim the nose up at low speed, the leading edge of the horizontal stabilizer tips down and the vertical stabilizer pivots forward. For nose down trim at cruise, the horiz stab leading edge tips up and the vert stab leading edge pivots back.
My dad owned the 201 (M20J) N58016 which had formerly been Roy LoPresti's "company car" and development mule for the 201, 231, and 252. Dad and Mom went to some Mooney Homecomings in Kerrville, where Roy gave him a guided tour of the bits that made that airframe unique.

The 'reversed' tail has been the signature feature on many of Mooney's products, including the M18, M20, M22 and the new production M10 line of aircraft.  But not every Mooney did use the design; best example of that was the Mooney 301, which evolved into the Daher Socata TBM series of single engine turboprops.
I've heard a lot of the reasons for this design choice, including improved rudder authority at high AoA listed above.  Another is that a trapezoidal shaped planform is a more efficient lifting surface design for slow subsonic flight where compreesibile effects are trivial.
Of interest, this tail plane design employs one of the most unorthodox elevator trim arrangements in aviation.  Starting with the M20E, the entire empennage is a single assembly which attaches to the aft fuselage via a single hinge point.  Driven by a pilot controlled screw jack, the entire empennage would then rotate in the vertical plane, thus changing the AoA of the tail plane and providing longitudinal trim. I'm not aware of any other aircraft which uses such a complicated elevator trim system including commercial aircraft which make use of an all moving tail plane box for this purpose.

The Mooney tail plane consists of three parts: vertical stab and L/R horizontal stab. All three are interchanging.

The tail plane surfaces on the M20 are not interchangeable.

When I picked up my mooney at the factory they showed me the single machine which makes the part

Which model do you have?


text:
Do I need special permission to land at a Landing Rights Airport?
According to the Chart Supplement, Orlando International airport (KMCO) is an LRA (landing rights airport).
What permission is needed to fly an aircraft to an airport classified as LRA? Can I just file a VFR flight plan, take off under VFR from somewhere in Florida, enter the class B with a clearance, and land there?

Also see 19 CFR 122.14 for requirements on getting permission to land. However a LRA seems to be only concerned with international flights, and you shouldn't have problems getting in as a domestic flight just getting in the air and getting clearance, however you'll want to call the tower before you leave to warn them and not tick somebody off trying to get commercial traffic in.

If you're thinking of flying a light GA aircraft, then this question is relevant

@Pondlife Yeah, that question is a good reference. However, MCO has 4 parallel runways, so you're not as likely to be messing things up as at, say, JFK.

@RonBeyer Yeah, the "Landing Rights Airport" designation isn't relevant on a flight from another part of Florida. It's just a CBP designation meaning CBP will allow you to land there as a port of entry to the USA.

According to the FAR's

(2) Private aircraft. The pilots of private aircraft are required to
  secure permission to land from CBP following transmission of the
  advance notice of arrival via an electronic data interchange system
  approved by CBP, pursuant to § 122.22. Prior to departure as defined
  in § 122.22(a), from a foreign port or place, the pilot of a private
  aircraft must receive a message from CBP that landing rights have been
  granted for that aircraft at a particular airport.

This only matters if you are inbound from an out of country origin. An LRA airport is

Landing rights airport. A landing rights airport is any airport, other than an international airport or user fee airport, at which flights from a foreign area are given permission by Customs to land.